<p><b>Abstract</b>—Although the original intent of the peer-to-peer (P2P) concept is to treat each participant equally, heterogeneity widely exists in deployed P2P networks. Peers are different from each other in many aspects, such as bandwidth, CPU power, and storage capacity. Some approaches have been proposed to take advantage of the <it>query forwarding heterogeneity</it> such that the high bandwidth of powerful nodes can be fully utilized to maximize the system capacity. In this paper, we suggest using the <it>query answering heterogeneity</it> to directly improve the search efficiency of P2P networks. In our proposed Differentiated Search (DiffSearch) algorithm, the peers with high query answering capabilities will have higher priority to be queried. Because the query answering capabilities are extremely unbalanced among peers, a high query success rate can be achieved by querying only a small portion of a network. The search traffic is significantly reduced due to the shrunken search space. Our trace analysis and simulation show that the DiffSearch algorithm can save up to 60 percent of search traffic.</p>